Fluidic oscillator for providing dynamic liquid spray patterns

ABSTRACT

A fluidic oscillator is capable of alternating between full and partial channel flow states. In the partial channel flow state a relatively high velocity jet flows straight through the oscillator interaction region and issues through a single outlet opening in a predetermined direction. In the full channel flow state a diffused output flow fills the interaction region and issues from the same outlet opening at a considerably slower velocity and at an angle relative to the high velocity jet. In a preferred embodiment the oscillator has an annular transverse cross-section which surrounds a central longitudinal feedback passage. A straight cylindrical outer sidewall of the interaction region extends adjacent the high velocity jet, which issues when ambient air enters the feedback passage. Part of the high velocity jet is fed back into the interaction region to reduce the pressure therein and initiate full channel flow. The inner interaction region sidewall has a semi-teardrop configured longitudinal cross-section and combines with the outer sidewall to direct the full channel flow away from the feedback passage, permitting ambient air to re-enter the interaction region and reinitiate the partial channel flow state. The resulting spray of flow pattern alternately widens and narrows and is suitable for shower heads, sink sprays, decorative fountains, etc. In one embodiment an adjustment is provided to block ambient air from the interaction region to permit a steady, unaerated, fullchannel outflow.

United States Patent 1191 Bauer 1111 3,820,716 June 28, 1974 1 FLUIDIC OSCILLATOR FOR PROVIDING DYNAMIC LIQUID SPRAY PATTERNS [75] Inventor: Peter Bauer, Germantown, Md.

[73] Assignee: Bowles Fluidics Corporation, Silver Spring, Md.

[22] Filed: Jan. 11, 1973 [21] Appl. No.: 322,608

Primary Examiner-Lloyd L. King Assistant Examiner-Michael Y. Mar Attorney, Agent, or Firm-Rose & Edell 57 ABSTRACT A fluidic oscillator is capable of alternating between full and partial channel flow states. 1n the partial channel flow state a relatively high velocity jet flows straight through the oscillator interaction region and issues through a single outlet opening in a predetermined direction. In the full channel flow state a diffused output flow fills the interaction region and issues from'the same outlet opening at a considerably slower velocity and at an angle relative to the high velocity jet. In a preferred embodiment the oscillator has an annular transversecross-section which surrounds a central longitudinal feedback passage. A straight cylindrical outer sidewall of the interaction region extends adjacent the high velocity jet, which issues when ambient air enters the feedback passage. Part of the high velocity jet is fed back into the interaction region to reduce the pressure therein and initiate full channel flow. The inner interaction region sidewall has a semiteardrop configured longitudinal cross-section and combines with the outer sidewall to direct the full channel flow away from the feedback passage, permittingambient air tore-enter the interaction region and re-initiate the partial channel flow state. The resulting spray of flow pattern alternately widens and narrows and is suitable for-shower heads, sink sprays, decorative fountains, etc. In one embodiment an adjustment is provided to block ambient air from the interaction region to permit a steady, unaerated, full-channel outflow.

36 Claims, 15 Drawing Figures 29 28 45 73 41 5'5 55 U2 1 T9 1 g 43 a 1 max 9 7s 89 65 IE A L 659 a -1- L5 L 21 1/1 4'1e I FLUIDIC OSCILLATOR FOR PROVIDING DYNAMIC LIQUID SPRAY PATTERNS and, more particularly to a novel fluidic oscillator capable of providing a dynamic liquid spray or flow pattern having a wide variety of uses.

The use of fluidic oscillators in spray devices to provide dynamic i.e. continuously changing) spray or flow patterns is well known. For example, fluidic oscillators have been employed to provide dynamic spray patterns in: shower heads. as described in my U.S. Pat. No. 3,563,462 and my US. Pat. No. 3,741,481; in'lawn sprinklers, as described in [1.8. Pat. No. 3,432,102; in decorative fountains, as. described in U.S. Pat. No. 3,595 ,479; in water picks and other cleaning apparatus, as described in US. Pat. No. 3,468,325; etc. Most of these oscillators produce spray patterns which are suitable only for use in the specific apparatus for which they were designed and lack flexibility for use in other applications. I have found, however, that the dynamic flow pattern described in relation toFIGS. 9'and 10 of my aforementioned US. Pat. No. 3,741,481 (incorporated herein by reference) has a wide variety of uses. Specifically, that spray pattern oscillates between a relatively wide conical configuration and somewhat narrow conical or cylindrical core configuration; that is, the spray pattern appears to repetitively open and close. This spray pattern not only has a pleasing effect for a bather, but it has been found to have numerous other uses, suchas cleaning of surfaces, decorative sprays, sterilization of body parts, etc.

Referring specifically to the oscillator disclosed in FIG. 9 of my prior US. Pat. No. 3,741,481, the output spray pattern oscillates between two conditions: in one condition the output flow comprises a relatively high velocity liquid jet directed along one wall of the oscillator output region; in the other condition the output flow spreads and fills the entire output region, providing a slower movingflow. The alternating velocity,

combined with the alternating pattern configuration,

has been. found to provide an exceptionally pleasing effect as a shower spray. Moreover, the pulsating velocity effect has been found to be desirable for dislodging dirt from surfaces, etc. As a'practical matter, however, this oscillator has proven to be difficult to manufacturebecause ,it requires both a crossover feedback path and a vent channel communicating with respective opposite sides of the oscillator interaction region.

The oscillator described in relation to FIG. 10 of my aforementioned U.S. Pat. No. 3,741,481 does away with the crossover feedback path by employing an interaction region having curved sidewalls which are configured to reverse the main jet direction after the jet is deflected. However, this oscillator is only capable of oscillating the jet and does not have a full channel flow condition. This oscillator, therefore, does not have the advantage of alternating velocity in the output spray pattern but instead is restricted to an alternating spray configuration. Moreover, the two curved flowreversing walls in the oscillator interaction region add a complexity factor to this oscillator.

I have found that, apart from oscillation, the full channel flow condition of the oscillator, if maintained in steady state, is desirable for use in conjunction with kitchen sink faucets. Specifically, the steady full channel flow condition results in a low velocity soft" stream which is devoid of aeration bubbles. Such a stream is desirable for drinking water in that it avoids the *cloudy" effect produced by aeration in glasses of water filled from most faucets. A most desirable faucet attachment, therefore, would be a spray member which is adjustable to have a steady full channel flow in one mode and an oscillating velocity and spray configuration in a second or dish washing mode.

It is therefore an object of the present invention to provide a fluidic oscillator configuration capable of use in a wide variety of spray apparatus.

It is another object of the present invention to provide an easily constructed fluidic oscillator capable of providing a dynamic spray pattern in which the spray configuration and spray velocity alternate automatically.

It is another object of the present invention to provide an easily fabricated shower head employing a fluidic oscillator to provide a spray pattern which alternately widens and narrows.

It is another object of the present invention. to provide a spray member capable of providing a steady,

non-aerated output flow in one mode and an oscillatory flow in another mode It is still another object of the present invention to provide a fluidic spray apparatus capable of providing a variety of uniquely decorative spray patterns for use in decorative fountains or the like.

SUMMARY OF THE INVENTION .sectional configuration. The straight outer wall terminates abruptly at an annular outer edge; the inner wall also terminates abruptly at an annular inner edge slightly downstream and radially inward of the outer edge. The two annular edges define an annular outlet opening for the oscillator. A substantially straight cylindrical guide wall extends downstream from the annular inner edge of the outletopening and includes one or more openings which communicate with a central feedback passage. The feedback passage extends along the longitudinal axis of the various annular passages and openings to the upstream end of the interaction region. If the feedback passage is open to ambient the jet issued by the power nozzle flows generally along the 1 straight outer wall of the interaction region, out through the annular outlet opening, and along the cylindrical guide wall. Part of this liquid flow enters the guide wall openings and into the feedback passage. When enough of the fed back liquid enters the passage, ambient air is blocked and the annular jet issued from the power nozzle is no longer unconstrained. The jet then spreads to fill the entire interaction region and is redirected by the sidewalls to flow through the outlet opening at an outwardly divergent angle relative to the guide wall. The resultant spray or flow pattern covers a wider area than the free jet issued in the previously described state of the oscillator. Air is thus permitted to enter the feedback passage to return the oscillator to its former state and oscillation continues in this manner.

The outlet region of the apparatus may be configured to direct the flow pattern, in its widened state, at whatever angle is suitable for the apparatus. In addition, the feedback passage may be rendered adjustable to change the duty cycle of the oscillator. Moreover, by adjustably blocking flow of ambient air into the interaction region, the apparatus can be made to operate in a steady full channel flow state in which a soft, unaerated flow is provided.

BRIEF DESCRIPTION OF THE DRAWINGS The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed descrip tion of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a view in section, taken along lines ll of FIG. 2, of a shower head employing the fluidic oscillator of the present invention;

FIG. 2 is an end view of the shower head of FIG. 1;

FIG. 3 is an end view of an adjustment screw employed in the feedback passage of the shower head of FIG. 1;

FIG. 4 is a diagrammatic view of the shower head of FIG. 1 illustrating one of the two alternating flow states;

FIG. 5 is a diagrammatic view of the shower head of FIG. 1 illustrating the other of the two alternating flow states;

FIG. 6 is a side view in partial section showing a typical mounting arrangement for the shower head of FIG. 1;

FIG. 7 is a partially diagrammatic view in section of a sink spray apparatus employing the fluidic oscillator of the present invention and illustrating the steady full channel'flow mode of the apparatus;

FIG. 8 is 'a similar view in section of the apparatus of FIG. 7, wherein the apparatus has been adjusted to permit ambient air inflow to cause oscillatory spray operation;

FIG. 9 is a view in section ofa modified sink spray apparatus employing the fluidic oscillator of the present invention;

FIG. 10 is a view in partial section of another modified sink spray apparatus employing the fluidic oscillator of the present invention;

FIG. 11 is a view in section of a decorative fountain spray apparatus employing the fluidic oscillator of the present invention;

FIG. 12 is a view in perspective of a flow-directing member employed with the apparatus of FIG. 11;

FIG. 13 is a diagrammatic illustration of the apparatus of FIG. 11 in a typical operating environment;

FIG. 14 is a diagrammatic view of one of two alternating flow patterns produced by the apparatus of FIG. 11; and

FIG. 15 is a diagrammatic view of the other of the two alternating flow patterns produced by the apparatus of FIG. 11.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring specifically to FIGS. 1, 2 and 3 of the accompanying drawings, a shower head 10, disposed axi-symmetrically about axis A-A. is formed from five primary components, namely: housing 11; jet metering member 12; nozzle member 13; barrel 14; and needle valve 15. The components are preferably formed of a hard. water-repellent plastic but may be made of suitable rust-resistant metal if desired.

The outer periphery of housing 11 includes a series of cylindrical sections of various diameter. most of which are arranged to fit within the interior of barrel 14. Three sections of the housing periphery require specific mention; these are: threaded section 17, located at the inlet or upstream end of the shower head; radially extending flange 19 located proximate the outlet or downstream end of the shower head; and a small annular chamfer 21 formed between the inlet and outlet ends approximately one-third the way from the inlet end. Chamfer 21 forms an annular ramp which diverges radially outward for a short distance toward the outlet end and terminates abruptly to provide a radially inward-extending annular shoulder which faces the outlet end of the shower head. Flange 19 includes a radially extending annular surface 20 which faces the inlet end of the shower head.

The interior of housing 11 is hollow and includes three distinct sections. A first cylindrical section 23 extends a short distance from the inlet end of the shower head before terminating in a radially inward-extending shoulder 25 which demarks the start of a second cylindrical section 27 of somewhat smaller diameter than section 23. Section 27 constitutes most of the length of the housing interior and terminates at the inner annular edge 28 of an outwardly-extending shoulder 29. The remainder of the housing interior includes a frustoconical section 31 which flares outwardly from shoulder 29 to the downstream or outlet end of the shower head.

The outer surface of barrel 14 has a generally frustoconical configuration, flaring outwardly in a downstream direction. This outer surface may be provided with ridges 33 or other decorative configurations. The interior of barrel 14 is arranged to engage the periphery of housing 11. Specifically, the inner surface of barrel 14 is provided with a radially extending shoulder 35 located proximate the upstream end of the barrel and arranged to engage the shoulder terminating chamfer 21 on housing 11. A second shoulder 37 is provided proximate the downstream end of the barrel interior and is arranged to abut a portion of surface 20 of flange 19. In assembling the shower head, barrel 14 is pushed over the inlet end of housing 11 until shoulder 35 is pushed past chamfer 21 and snaps into place.

Metering jet member 12 includes a cylindrical section 41 through which six longitudinally extending liquid inlet holes 43 extend. Inlet holes 43 are equally and radially spaced from axis A-A. Section 41 is adapted to fit within cylindrical section 23 in the interior of housing 11. A chamfer 45, similar to chamfer 21 but diverging instead of an upstream direction, is provided in the periphery of section 41 and is adapted for snapfit engagement in a mating groove 47 formed in housing section 23.

Immediately downstream of section 41, jet metering member 12 is provided with a short, small-diameter,

cylindrical section which is followed by a somewhat larger-diameter cylindrical section 51. The space be tween the periphery of section 51 and section 27 of the housing interior defines an annular power nozzle 53.

Continuing in a downstream direction along jet meteringmember 12, section 51 is followed by a short frusto-conical section 55 of decreasing diameter. The smallest diameter of section 55 defines the diameter of the following cylindrical section 57 which is provided with six radiallyextending holes 59 which terminate at one end of a longitudinal bore. Bore 61 extends along axis A-A from holes 59 to the downstream end of jet metering member 12. Cylindrical section 57 is followed by another cylindrical section 63 of slightly smaller diameter, the junction between the two sections being defined by a radially-extending annular shoulder. Section 63 terminates jet metering member 12.

The upstream end of nozzle member 13 comprises a hollow cylindrical section 65 whichis adapted to surround section 57 of jet metering member. The inner surface of section 65 is radially spaced from jet meter ing member 12 to define an annular flow passage 67 which communicates, via radial holes 59, with bore 61. The upstream end of section 65 is also spaced from jet metering member 12 so that annular flow passage 67 extends past the end of section 65 to define an annular, radially outwardly-extending control port 69 proximate section 55 of the jet metering member.

The outer diameter of section 65 is slightly smaller than the outer diameter of section 51 of jet metering member 12; therefore section 65 is recessed relative to section 51 and the annularpassage 71 formed downstream of control port 69 is slightly wider than annular power nozzle 53. Passage 71 constitutes the upstream portion of an interaction region of a fluidic oscillator.

Downstream of section 65 the exterior of nozzle member 13 is contoured to form an annular curved sidewall 73 for the interaction region] Proceeding in a downstream direction, annular sidewall 73 gradually converges inwardly and then begins to diverge sharply outward starting at an axial location just prior to shoulder 29 and terminating at a sharp annular edge 75 just beyond shoulder 29. The extent of the reverse or outward curve in sidewall 73 is a matter of choice, depending upon the outflow direction desired. Importantly, however, annular edge 75 has a diameter which is slightly less than (or at worst equal to) the outside diameter of section 65. Consequently, the radial spacing between axially displaced annular edges 28 and 75 is at least as great as the width of annular flow passage 71. The annular opening between edges 28 and 75 constitutes the outlet opening 76 for the fluidic oscillator. The longitudinal cross-section of the interaction region formed between straight sidewall 27 and curved sidewall 73 may best be described as a semi-teardrop.

Downstream of edge 75 the outer surface of nozzle member 13 is cylindrical, extending axially toward the downstream end of the shower head. This region of the nozzle member constitutes a cylindrical flow guide wall 77. Guide wall 77 may be tapered slightly in either direction to guide outflow as desired.

The downstream end of guide wall 77 is bent or otherwise contoured at two or more locations to provide radial openings to the hollow interior of the nozzle member. These openings are designated as feedback openings 78 for reasons to by fully described.

The interior section 79 of nozzle member 13 immediately downstream of section has a generally cylindrical configuration and is adapted to receive cylindrical section 63 of jet metering member 12 in snap-fit or press-fit relation. To this end section 61 is provided with an annular chamfer adapted to fit into an annular groove in section 73 so as to prevent movement to the right (as viewed in FIG. 1) of nozzle member 13 relative to jet metering member 12.

Downstream of section 79, nozzle member 13 is provided with an axially extending cylindrical bore 81 which aligns with bore 61 in the jet metering member. The downstream end of bore 81 tapers outwardly and terminates in a somewhat larger threaded bore 83.

Threaded bore 83 is adapted to engage the externally threaded portion of the stem of needle valve 15, the point of which adjustably projects into bore 81. Needle valve 15 has a pair of longitudinally-extending channels 85, 87 defined in its threaded stem portion. The upstream, unthreaded portion of the needle valve stem is of substantially smaller diameter than the threaded por tion and is terminated by a knurled cylindrical knob 89 having approximately the same outside diameter as guide wall 77. When the needle valve is opened, a flow passage exists from feedback openings 78, channels 85, 87, bores 81 and 61, holes 59, and flow passage 67 to control port 69. When the needle valve is closed the tapered valve stem blocks flow communication between bore 81 and channels 85, 87.

Operation of the shower head of FIG. 1 is best described in relation to FIGS. 4 and 5 of the accompanying drawings. In FIG. 4 the needle valve 15 is open, permitting the fluidic oscillator to oscillate. Pressurized water (or other liquid) is admitted to the device at inlet holes 43 and is applied to annular power nozzle 53. The power nozzle issues a power jet into annular flow path 71 of the oscillator interaction region. The configuration of the power jet in this flow passage depends upon the conditions at radial control port 69; that is, the configuration of the jet in passage 71 depends upon whether air or water flows to the control port via the feedback path. Assume that needle valve 15 is open, as illustrated in FIG. 4, and that ambient air is free to flow through the feedback path (openings 79, channels 85,

87, boxes 61, 81) to controlport 69. The annular power jet in flow path 71 flows straight through the interaction region adjacent straight sidewall 27. Ambient air is free to enter the widened portion of the interaction region, between the annular jet and curved sidewall 73, thus maintaining the jet undisturbed and unconstrained as it flows adjacent straight sidewall 27, as illustrated in FIG. 4. The jet continues to flow straight out of the interaction region through outlet opening 76 and along guide wall 77, thereby maintaining its annular cross-section upon being issued from the outlet end of the shower head 10. A portion of the jet liquid, which now blocks ambient air inflow into feedback openings 78, enters the feedback. openings at the base of knob 89. In addition, the relatively high velocity of the jet, proximate control port 69, tends to aspirate fluid from the feedback passage, thereby further inducing entry of jet liquid into feedback openings 78. The fed back liquid, upon reaching control port 69, merges with the jet and causes it to diffuse and fill the entire interaction region. Upon filling the entire region between both sidewalls 27 and 73 (as illustrated in FIG. 5), the jet direction is determined by the contours of these sidewalls. (FIG. illustrates needle valve H5 closed; however, the steady full channel flow resulting from closure of the needle valve is the same condition as the astable full channel flow condition resulting from I blockage of the feedback openings by the power jet).

The directional contribution imparted to the jet by curved sidewall 73 imparts a radially outward velocity component; the contribution of straight sidewall 27 is to restrain or limit the degree of jet divergence. The resulting flow thus proceeds toward diverging wall 31 which acts as a guide for the outflow in this state. Since the jet no longer blocks feedback openings 78, ambient air is once again admitted to the feedback passage and causes the jet to return to its partial channel flow state. The oscillation cycle repeats in the manner described.

In the partial channel flow mode illustrated in FIG. 4, the shower head spray pattern takes the form of a high velocity jet or spray of relatively narrow annular cross-section and covers a relatively small area. In the full-channel flow mode illustrated in FIG. 5, the shower head spray pattern has a significantly wider annular cross-section and provides wider converage. The spray pattern thus continuously alternates between wide and narrow (or open and closed) states. Moreover, since the jet velocity is slower in the full channel flow mode than in the partial channel flow mode, the spray pattern contains an alternating or cyclic flow velocity component. The combination of alternating spray configuration and alternating spray velocity provides a pleasurable effect on the body of a person using the shower head as well as providing an efficient cleansing action.

With respect to the velocity difference between the full and partial channel flow states, it is important to note that this difference depends. upon the configuration' of the widened portion of the interaction region. The frequency of oscillation depends upon the pressure of the liquid supplied to the shower head. For one practical embodiment l have found that a frequency of 1800 to 2000 cycles per minute is obtained at a supply pressure of 30 psi. The configuration of the interaction region effects the delay during the full channel flow mode, the larger the interaction region, the greater the delay. I have found that it is possible to delay the full channel flow sufficiently so that outflow from both states is time coincident upon egressing from the shower head. Under such conditions the spray pattern is in the form of discrete annular pulses of liquid with the outer portion riding on the high velocity core. These pulses lose their annular configuration as they move farther from the shower head, resulting in full coverage liquid pulses. These pulses have a pleasing effect on the bathers body; more importantly these pulses have a cleansing effect which is much greater than that provided by a conventional shower spray. Specifically, it has been found that pulsating water jets and sprays have a sterilizing effect on skin by virtue of the fact that the pulses destory and quickly remove bacteria therefrom (reference: Effectiveness of Pulsating Water Jet Lavage in Treatment of Contaminated Crushed Wounds," by A. Gross et al., published in The American Journal of Surgery, Volume 124, pages 373-377, September 1972, and therein). Shower head 10 therefore provides an important preventive health function as well as a pleasing sensation for the user.

references citedv As illustrated in FIG. 5, when needle valve 15 is closed, no ambient air can enter the feedback passage. The oscillator is thus maintained in its full channel flow mode wherein the relatively wide flow pattern issues steadily from the shower head. Simple adjustment of knob 89 permits the user to select the oscillating or steady flow conditions.

It should be pointed out that the angle subtended between wall 31 and axis A--A' in the outlet region of the shower head is a matter of choice and can be selected to provide whatever degree of spray divergence is desired or required for a particular apparatus. Moreover, as described in my aforementioned US. Patent application Ser. No. 163,566, the outlet region may be subdivided into multiple individual passages having varied angles with respect to axis AA, so that a spray pattern comprising multiple individual spray elements is provided. The comb-like structure described in said patent application for providing the multiple spray elements may be in the form of an adapter which can be inserted into the outlet region or not by the user.

It should also be pointed out that guide wall 77 can diverge or converge slightly if desired for a particular apparatus.

Apart from permitting the user to select between oscillating and steady flow patterns, needle valve 15 is adjustable over a range of openings to permit the oscillation duty cycle to be varied. As the valve is opened to a greater extent, the duty cycle of the high velocity narrow pattern increases; that is, the narrow pattern subsists for an increasing portion of the oscillation cycle. Likewise, narrowing the valve opening increases that portion of the cycle in which the wider pattern subsists. ln this respect it should be pointed out that the feedback passage is sensitive to two parameters: length, which establishes the oscillation frequency; and flow impedance, which affects duty cycle and has negligible affect on frequency. Thus, the length of the feedback passage is selected to provide the desired frequency for the expected range of operating pressures. If desired the feedback passage can be provided with bends, etc., to increase its length if a low frequency is desired. On the other hand the needle valve constitutes a flow restrictor which is part of the overall flow impedance in the feedback path. Therefore the needle valve permits duty cycle adjustment. Supply pressure variations also affect duty cycle; that is, the greater the supply pressure, the greater is the full channel flow portion of the oscillation cycle. Needle valve 15 thus permits the user to adjust the duty cycle as desired for different available supply pressures.

Another important advantage of shower head 10 is its simplicity and ease of fabrication. Specifically, the shower head includes five pre-fo'rmed or molded parts which are simply snapped or threaded together. It is thus conducive to low cost mass production runs.

While the oscillation as described above is of annular transverse cross-section having a central feedback core, the basic concept of the oscillation is adaptable to planar devices. Planar fluidic elements are conventional and this embodiment need not be described in detail except to state that such an element is simple to construct in view of the fact that the interaction region simply has a straight sidewall and a curved sidewall and does not require the conventional flow splitter. A single outlet opening from which flow can issue in either of two directions further contributes to fabrication simplicity.

FIG. 6 of the accompanying drawings illustrates a I typical mounting arrangement for shower head 10. A

hollow generally cylindrical socket member 91 is internally threaded at one end and is adapted to engage threaded-portion 17 of housing 11 of the shower head. The other end of socket member 91'is adapted to cap ture a generally spherical projection 93 at one end of a hollow mounting member 95. Spherical projection 93 is captured in a'ball and socket arrangement whereby socket member 91 is permitted universal rotation rela tive to mounting member 95. The other end of mounting member 95 is internally threaded to be secured to a standard shower plumbing installation. It is possible of course to provide other mounting arrangements for the shower head, such as the hand-shower mounting arrangement described in my aforementioned U.S. Patent application Ser. No. 163,566.

The oscillator employed in shower head has a varietyof other uses. One other such use is illustrated in FIGS. 7 and 8 of the accompanying drawings wherein a sink spray adapter 100 is illustrated. Adapter 100 includes an inner housing member 101, a metering jet member 102, a nozzle member 103, and an outer housing member 104. All components are axi-symmetric about axis BB'. The central core of the adapter is provided by the hollow interior of inner housing 101 which receives metering jet member 102 and nozzle member 103 in a manner similar to that in which housing member 11 of shower head 10 receives metering jet member 11 and nozzle member 12. However, threaded engagement is provided between inner housing 101 and metering jet member 102 rather than a snap fit. The externally-threaded portion 106 of metering jet member 102 which engages inner housing 101 extends beyond the inner housing and is adapted to be engaged by astandard sink faucet plumbing fixture. Appropriate longitudinally-extending inlet holes 107 at the up stream end of metering jet member 102 permit entry into the adapter of pressurized liquid.

Instead of the snap fit engagement between barrel 14 and housing 11 as provided in shower head 10, outer housing 104 is internally threaded to engage an externally threaded section of inner housing 101 at 109. Longitudinally-extending channel 111 is defined along this threaded portion of inner housing 101. When outer housing 104 is fully tightened relative tothe inner housing via threaded engagement 109 (as illustrated in FIG. 7), channels 111 are blocked at both ends from communication with ambient. At their upstream ends channels 111 are sealed by virtue of the fact that the upstream edge 113 of outer housing 104 abuts a shoulder 115 of inner housing 101; at the downstream end of channels 111 an inwardly projecting annular edge 117 of outer housing abuts the outer wall of inner housing 101.

When threaded engagement 109 is loosened somewhat (as illustrated in FIG. 8), channels 111 communicate between ambient air and the outlet region of the oscillator. Specifically, the upstream edge 103 of outer housing 104 is displaced from inner housing shoulder 115 to permit ambient air to enter the channels. Likewise, annular edge l17 is displaced downstream of inner housing 101 to provide an opening 119 from the channels 111 into the oscillator interaction region.

The interior of the sink adapter oscillator is constructed in a manner similar to the shower head oscillator. An annular power nozzle 121 is formed between the inner housing 101 and metering jet member 102. The interaction region is defined between inner housing 101 and nozzle member 103 and includes an .upstream annular flow passage 125 and a downstream re gion defined between straight wall 127 of the inner housing and curved wall 129 contoured in the nozzle member. Straight wall 127 defines one side of power nozzle 121 as well as one side of the interaction region. The separation between the annular edges of walls 127 and 129 defines an annular outlet opening 131 for the interaction region.

There is no counterpart to needle valve 15 in sink adapter 100. Feedback openings are in the form of ra dial holes 137 defined through flow guidewall and extending into the central longitudinal feedback bore 139 extending through nozzle member 103. Feedback bore 139 aligns with one end of a similar bore 141 in metering jet member 102, the other end of which terminates in radial flow passages 143. Passages 143 communicate with annular control port 123.

When threaded engagement 109 is tightened, as illustrated in FIG. 7, the adapter assumes a steady full channel flow mode. Specifically, the full channel flow mode is sustained by virtue of the fact that the outlet region of sink adapter 100 is somewhat narrower than the outlet region of shower head 10. Consequently, the full channel flow from the interaction region tends to also fill the outlet region. In so doing it blocks feedback opening 137 and prevents ambient air from entering the feedback passage and switching the oscillator to its partial channel flow mode. Closure of channels 111 prevent ambient air from entering the outlet region and thereby permits the outflow to fully diffuse in the outlet region.

If threaded engagement 109 is loosened, as illustrated in FIG. 8, ambient air is aspiratedthrough channels 111 and into the outlet region. The air tends to mix with the liquid in the outlet region, forming air bubbles, some of which migrate through the outlet region to the low pressure region along guide wall 135. A significant volume of these air bubbles is drawn into the feedback passage through openings 137 to control port 123. Full channel flow cannot be sustained in the presence of the air entering the feedback passage; the jet is thus restored to the partial channel mode, flowing substantially unconstrained adjacent straight wall 127, as in shower head 10. The narrow annular spray pattern resulting from the partial channel flow permits air from channel 111 to be vented via the region between the I issued jet and the outer wall of the outlet region. The

feedback openings 137 are thus sealed to ambient air and supply only liquid to the feedback path. As described above, this causes power jet diffusion and expansion at control nozzle 123 and restores full channel flow. The low velocity full channel flow in the outlet region once again permits air bubbles from channels 111 to be aspirated and enter the feedback passage, thereby continuing the oscillation.

An important feature of the sink adapter is that in the steady full channel flow mode i.e. with channels 111 closed as in FIG. 7) the low velocity output flow is soft," so as to produce minimal splash on impact, and is not aerated. The lack of aeration results from the fact that no ambient air enters the adapter in this mode and therefore no air is aspirated by the low velocity jet. The lack of aeration is ideal for drinking water which, by virtue of the adapter, can be made devoid of the cloudy effect normally caused by air bubbles.

The versatility of adapter 100 is evident. On the one hand it permits soft outflow suitable, inter alia, for providing clear drinking water. On the other hand it provides a sweeping dynamic spray pattern of alternating velocity which is ideal for loosening dirt from dishes, silverware, etc.

FIG. 9 illustrates a modified sink adapter 100a. In adapters 100 and 100a like components are provided with like reference numerals. The features which distinguish adapter 100a from adapter 100 are as follows:

1. The overall length of adapter 100a is shorter than adapter 100. The length reduction is reflected throughout the entire unit but primarily in the outlet region.

2. The outlet region is significantly narrower. In fact the outlet region of adapter 100a converges slightly in a downstream direction by virtue of the fact that guide wall 135 diverges slightly (about and the outer wall divergence is reduced to less than that of guide wall 135. This shorter, narrower outlet region is more efficient in producing the unaerated full channel outflow mode than the wider outlet region of adapter 100. This is because the full channel outflow is compacted by the narrower outlet region of adapter 100a and provides both a more positive seal against entry of ambient air into the feedback passage and a better assurance against aspiration of air into the flow through the outlet region. 7

3. Channels Ill communicate directly with the upstream end of the interaction region via openings 145. This aids to insure an oscillatory mode when threaded engagement 109 is opened. This assurance is required since the shortening and narrowing of the outlet region tends to favor sustaining full channel flow and makes it more difficult for air bubbles to cross the outlet region to the feedback path. Ambient air inflow through openings 145 assure that sufficient ambient air can be supplied to permit oscillation.

4. Straight wall 127 is recessed outward in the interaction region relative to the power nozzle 121. This also helps to assure oscillation by providing greater ambient air access to the interaction region and thereby assuring that the partial channel flow state can be achieved.

It will be apparent that a variety of modifications, employing the basic fluidic oscillator approach, are capable of providing a sink spray adapter of the type de-' scribed. One other such modification is illustrated in FIG. 10 wherein like reference numerals are employed to designate elements having counterparts in FIG. 7. The major difference in the adapterof FIG. 10 resides in the fact that channels 111 have been omitted and ambient air entry into the interaction region is permitted only via the outlet end of the adapter. Inner housing 101 differs from inner housing 101 in FIG. 7 primarily by virtue of the fact that it is in slidable rather than threaded engagement with outer housing 104'. An 0- ring 142 is inserted in an annular groove provided about the outer periphery of inner housing 101, proximate its downstream end. The inner diameter of outer housing 104 is made equal to or slightly less than the outside diameter of O-ring 142 so that the O-ring provides a fluid-tight annular seal between the two housings as outer housing 104 is slid axially along inner housing 101.

A ridge or projection 148 extends radially inward from the downstream end of outer housing 104. The upstream shoulder of ridge 148 abuts the downstream edge of inner housing 101 when outer housing 104 is in its fully retracted (i.e. upstream) position. In inner diameter of ridge 148 is less than the inner diameter of the downstream edge of inner housing 101. When outer housing 104' is fully protracted (i.e. full downstream), ridge 148 extends downstream beyond the downstream end of nozzle member 103.

A guide pin 146 is secured in outer housing 104' and extends radially inward into a longitudinally-extending groove 144 defined in the outer periphery of inner housing 101. Guide pin 146 and groove 144 cooperate to limit the extent to which outer housing 104' can be protracted, thereby preventing outer housing 104 from being pulled off and away from the adapter.

An interesting characteristic of the adapter of FIG. 10 is that it is mode switchable in response to both the position of outer housing 104 and the supply pressure.- Specifically, when the outer housing is fully retracted (as illustrated by solid lines in FIG. 10) the operating mode depends upon the liquid supply pressure. At low pressure the element assumes a steady full channel flow mode wherein the outflow is a continuous soft and unaerated stream. At higher supply pressures the outflow oscillates between the two positions indicated by the dashed flow lines in FIG. 10. As indicated, the degree of divergence by the spray in its relatively wide configuration is limited by ridge 148 which effectively narrows the outlet opening. This outlet-narrowing effect is important also in the low supply pressure, full channel mode wherein ridge 148 limits the entry of ambient air into the interaction region.

When housing 104 is fully protracted, as illustrated by dotted lines, the element provides steady full chan nel flow in response to substantially all practical liquid supply pressures. The protraction of outer housing 104 displaces the only possible ambient air ingress further downstream of the interaction region and the feedback openings, thereby substantially increasing the effective impedance to ambient air inflow. As described above, ambient air is required in the interaction region to effect the partial channel flow mode. If little or no ambient air enters the interaction, as is the case when the outer housing is fully protracted, full channel flow is maintained and no oscillation occurs.

Another utilization of the fluidic oscillation of the present invention is illustrated in the form of a decorative fountain spray apparatus 150 in FIGS. 11 and 12; Apparatus 150 is provided with a threaded fitting at its upstream end to which a hose or other liquid conduit may be connected. The oscillator is basically the same as that employed in shower head 10. Specifically, an annular power nozzle 151 delivers a power jet into annular flow passage 153 at the upstream end of the interaction region. Downstream of passage 153 the interaction region is bounded by straight sidewall 157 and curved sidewall Flow is delivered through outlet opening 159 and along flow guide wall 161 during the partial channel flow mode of the oscillator; during full channel flow the outflow is directed alongthe flared outer wall 165 of the outlet region. The flare of the outer wall may be selected (as indicated by dotted line 165a) to provide a variety of desired flow patterns.

A hollow cylindrical extension member 167, sealed at its downstream end, is secured to the downstream end of apparatus 150. The outer wall 169 of the extension member provides a longitudinal extension of flow guidewall 161. The interior bore in the hollow extension member communicates via feedback passage 171 with annular control port 152 at the upstream end of the interaction region. An annular flow divider 173 is secured about extension member 167 proximate the downstream end thereof. Flow divider 173 includes a plurality of flow openings 175 equally spaced about its inner periphery adjacent extension wall 169. Slightly upstream of flow divider 173 there are defined a plurality of feedback openings 170 extending radially through the wall 169 of the extension member and communicating with the central bore. These openings may likewise be located downstream of the flow divider.

In operation, the apparatus of FIG. 11 is oriented with its longitudinal axis vertically disposed and its downstream end elevated. During the partial channel flow condition an annular jet is directed upward, surrounding extension member 167. Uponreaching flow divider 173 a portion of the jet passes through flow openings 175 and continues upward; the remainder of the jet is deflected to the side by the solid portion of the flow divider. In addition, a portion of the jet liquid enters feedback openings 170 and is conducted through the feedback path 171 to control port 152. This feedback liquid reduces the interaction region pressure and causes the oscillator to assume its full channel flow condition.

Full channel flow is directed out and away from the apparatus by outer wall 165 of the outlet region. Since no liquid from this spray enters feedback openings 170, ambient air soon fills the feedback path and restored the partial channel flow condition. Oscillation continues in this manner. providing a dynamic decorative spray apparatus having no moving parts.

A diagrammatic illustration of typical operation for spray apparatus 150 is provided in FIGS. 13, 14 and 15. In FIG. 13 spray apparatus 150 is secured to a float 181 located on the surface of a pool 183. Liquid supply is provided by pump 187 through hose 185. The decorative spray pattern illustrated in FIG. 14 is provided in response to the full channel flow mode of the oscillator; the pattern in FIG. 15 is provided during the partial channel flow mode. The combined spray pattern effect is illustrated in FIG. 13. I

In an alternative construction, extension member 167 may be open at its downstream end. This permits a portion of the upwardly-directed jet liquid in the partial path to effect oscillation. This construction may or may not utilize feedback openings 170.

The oscillator embodiments described above are intended primarily to operate with a liquid working in an ambient air environment. It should be noted, however,

that the oscillator is capable of operation beneath the surface of a liquid body if air lines are provided which permit the oscillator. to assume its partial channel flow for objects and articles immersed in the liquid. Moreover, air bubbles are introduced into the liquid during the partial channel flow condition; these bubbles not only aerate the liquid body but induce a microflotation effect wherein the bubbles themselves attract dirt particles and carry them to the surface where they can be drained or otherwise removed. 'Another underwater function to be served by the oscillator is whirlpool bathing which is most easily effected by the agitation described above. i

It will also be appreciated that the oscillator disclosed herein is uniquely advantageous for functions other than those expressly disclosed. Among these functions are lawn sprinklers, water picks, etc.

An important characteristic of the oscillator of the present invention is its ability to provide jet velocity augmentation. This phenomenon is known in the prior art and is created when the onset of a slug or jet of relatively dense fluid (such as water) approaches a constriction in a flow passage which had been previously occupied by a fluid of lesser density, such as air. The initial portion of the dense fluid slug or jet is accelerated at the constriction relative to the remainder of the slug or jet. Upon leaving the constriction the accelerated portion of the slug or jet effectively runs away from the remainder of the slug or jet and impinges with greater force against a blocking surface than does the remainder of the slug or jet. In the oscillator of the present invention this velocity augmentation effect occurs at the outlet opening when the leading edge of a full channel flow approaches the constricted outlet opening. For example, in FIG. 1 this velocity agumentation occurs at outlet opening 76 which constricts the full channel flow received from the widened portion of the interaction region. This augmentation occurs once during each oscillation cycle as the oscillator changes from partial to full channel flow operation. It is possible to obtain velocity augmentation of a'factor of four or more. This velocity augmentation is particularly advantageous in the shower head where the high velocity pul' sations are effective in cleaning the body and, as described herein, are effective in destroying and removing bacteria. Likewise, the velocity augmented impulses are also effective in the sink adapter toloosen dirt from dishes, silverwave, glassware, and other objects.

While jet velocity augmentation has been previously achieved, it has not been previously achieved in a fluidic oscillator by virtue of oscillation between full and partial channel flowconditions. The important structural feature of my oscillator which permits velocity augmentation is the single interaction region channel which constricts at its outlet end.

While .I have described and illustrated specific embodiments of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit: and scope of the invention as defined in the appended claims.

I claim: 1. A fluidic oscillator comprising: an interaction region having upstream and downstream ends, a substantially straight sidewall terminating abruptly proximate said downstream end,

and a curved sidewall whiclh diverges gradually from said straight sidewall in a downstream direction and curves sharply back toward said straight sidewall at said downstream end, said curved sidewall terminating slightly downstream of said straight sidewall, the terminations of said sidewalls defining an outlet opening at the downstream end of said interaction region; power nozzle located at the upstream end of said interaction region and arranged to issue a jet of pressurized liquid into said interaction region, said jet being directed by said power nozzle generally adjacent said straight sidewall such that said jet issues undeflected through said outlet opening when ambient air is present in sufficient quantity in said interaction region to limit jet flow therethrough to a partial channel flow mode, said jet being deflected by said sidewalls to issue from said outlet opening at an angle into the plane of said straight sidewall when ambient air is sufficiently absent from said interaction region to cause said jet to assume a full channel flow mode therein; and

a feedback passage having an ingress opening and arranged to conduct ambient air to said interaction region when said ingress opening is unblocked, said ingress opening being positioned downstream of said outlet opening so as to be blocked to ambient air inflow when said liquid jet issues undeflected from said outlet opening and open to ambient air inflow when said liquid jet issues deflected from said outlet opening. 7

2. The oscillator according to claim 1 formed as an axi-symetrical element wherein said power nozzle, said interaction region and said outlet opening have annular transverse cross-sections which are concentric about said feedback passage, said interaction region having a longitudinal cross-section with a semi-teardrop configuration.

3. The element according to claim 1 further comprising a flow guide wall extending downstream from the termination of said curved sidewall and positioned to guide said liquid jet when issuing from said outlet opening undeflected, and wherein said ingress opening for said feedback passage comprises an opening defined in said guide wall.

4. The oscillator according to claim 3 wherein said feedback passage terminates in a control port opening through said curved sidewall into the upstream end of said interaction region.

5. The oscillator according to claim 4 constructed as an axisymmetrical element about said feedback passage, wherein said power nozzle, said interaction region and said outlet opening have annular transverse crosssections which surround said feedback passage, and wherein said curved sidewall comprises the radially innermost wall of said interaction region.

6. The oscillator according to claim 5 further comprising an annular outlet region extending downstream of said outlet opening and having as its inner boundary wall said flow guide wall.

7. The oscillator according to claim 6 further comprising an outer wall for said annular outlet region arranged to guide said liquid jet when it issues deflected from said outlet opening.

8. The oscillator according to claim 7 wherein said outer and inner walls of said outlet region diverge from one another in a downstream direction.

9. The oscillator according to claim 7 wherein said outer and inner walls of said outlet region converge toward one another in a downstream direction.

10. The oscillator according to claim 7 wherein said interaction region has a sufficiently large volume to delay the deflected jet issued from said outlet opening relative to the undeflected jet issued from said outlet opening.

11. The oscillator according to claim 7 further comprising:

a hollow housing having a first interior wall section of straight cylindrical configuration defining one side of said annular power nozzle and said straight sidewall of said interaction region. said housing having a second interior wall section downstream of said first interior wall section and defining said outer wall of said outlet region; and

member means disposed symmetrically within said hollow housing and spaced radially inward from said first and second interior wall sections of said hollow housing, said member means including: a first peripheral wall section of generally cylindrical configuration defining a second side of said annular power nozzle; a second peripheral wall section downstream of said first peripheral wall section and which at its upstream end is generally parallel to the first interior wall section of said hollow housing and then diverges and curves in a downstream direction to define said curved sidewall of said interaction region; and a third peripheral wall section defining said flow guide wall.

12. The oscillator according to claim 7 wherein the longitudinal position of the outer wall of said outlet region is movable relative to said flow guide wall.

13. The oscillator according to claim 12 wherein the outer wall of said outlet region comprises a generally cylindrical member surrounding the downstream portion of said oscillator and is longitudinally movable relative to said straight sidewall of said interaction region.

14. The oscillator according to claim 13 wherein said outer wall, in its fully retracted extreme upstream position, projects slightly downstream of said outlet opening and terminates upstream of said feedback openings in said flow guide wall; and wherein said outer wall, in its fully protracted extreme downstream position, projects beyond the downstream termination of said flow guide wall.

15. The oscillator according to claim 14 wherein said outer wall and said flow guide wall define a sufficiently narrow outlet region when said outer wall is fully protracted to limit ambient air inflow to less than that required to permit partial channel flow through said interaction region over a relatively wide range of liquid supply pressures.

16. The oscillator according to claim 14 wherein said outer wall, in its fully retracted position, defines a relatively narrow outlet opening with said flow guide wall such that for low liquid-supply pressures the liquid outflow during said full channel flow mode blocks all entry into said feedback openings and said interaction region and maintains said fully channel flow mode to prevent oscillation; and such that for higher pressures said liquid outflow during said full channel flow mode is sufficiently turbulent to permit ambient air to enter said feedback openings and maintain oscillation between said full and partial channel flow modes.

17. The oscillator according to claim 13 further comprising a fluid passage defined between said outer wall and the downstream portion of said oscillator, said fluid passage being arranged to conduct ambient air inflow to said interaction region when said outer wall is fully protracted and to be blocked to ambient air inflow when said outer wall is fully retracted. V

18. The oscillator according to claim 7 further comprising adjustable flow restriction means located in said feedbackpassage to permit controlled adjustment of the duty cycle of said oscillator.

19. The oscillator according to claim 18 wherein said adjustable flow restriction means has an extreme position in which said feedback passage is blocked to fluid flow, thereby limiting operation of said oscillator to its full channel flow mode.

20. The oscillator according to claim 18 wherein said adjustable flow restriction means comprises a needle valve projecting into said feedback passage from the downstream end of said oscillator and having an adjustment control located at the downstream end of said oscillator.

21. The oscillator according to claim 7 operable as a shower head and further comprising mounting means for securing said oscillator to a liquid supply in a shower plumbing installation.

22. The oscillator according to claim 7 operable as a sink faucet adapter and comprising means for securing said oscillator to a sink faucet.

23. The oscillator according to claim 7 arranged to provide decorative fountain spray patterns, wherein said flow guide wall extends a relatively long distance downstream of the outer wall of said outlet region.

24. The oscillator according to claim 23 further comprising an annular divider disposed about said guide wall proximate the downstream end of said guide wall, said flow divider including at least one longitudinallyextending opening positioned to conduct a portion of the liquid flowing along said guide wall through said flow divider, said flow divider being contoured to outwardly deflect that portion of the liquid which does not pass through said opening.

25. A fluidic oscillator comprising:

an interaction region of annular transverse crosssection having upstream and downstream ends, a substantially straight outer cylindrical sidewall terminating abruptly proximate said downstream end, and a curved inner sidewall which diverges gradually from said straight sidewall in a downstream direction and curves sharply back toward said straight sidewall at said downstream end, said curved sidewall terminating slightly downstream of said straight sidewall. the terminations of said sidewalls defining a single annular outlet opening at the downstream end of said interaction region;

an annular power nozzle located at the upstream end of said interaction region and arranged to issue an annular flow of pressurized liquid into said interaction region, said annular flow being directed by said power nozzle generally along said straight sidewall such that said annular flow issues undeflected through said outlet opening when ambient air is present in sufficient quantity in said interaction region to limit flow therethrough to a partial channel flow mode, said annular flow being deflected by said sidewalls to issue from said outlet opening at an angle into thecylindrical plane of said straight sidewall when ambient air is absent from said interaction region to cause said annular flow to assume a full channel flow mode therein; and

a feedback passage having an ingress opening and arranged to conduct; ambient air to said interaction region when said ingress opening is unblocked, said ingress opening being positioned downstream of said outlet opening so as to be blocked to ambient air inflow when said annular flow of liquid issues undeflected from said outlet. opening and open to ambient air inflow when said annular flow of liquid issues deflected from said outlet opening.

26. The fluidic oscillator according to claim 25 further comprising adjustable meansfor selectively limiting ambient air inflow to said interaction region to a sufficient extent as to prevent establishing of partial channel flow through said interaction region.

27. The fluidic oscillator according to claim 26 wherein said adjustable meanscomprises a valve disposed in said feedback passage.

28. The oscillator according to claim 26 wherein said adjustable means comprises an outer wall for said oscil lator, said outer wall being adjustably positioned longi tudinally relative to said oscillator such that in its fully extended position it projects beyond the downstream end of said oscillator and in its fully retracted position it terminates upstream of the downstream end of said oscillator.

29. The oscillator according to claim 25 further comprising a generally cylindrical flow guide wall extending downstream from the termination of said curved side wall and positioned to guide said annular flow of liquid when it issues from said outlet opening undeflected.

30. The fluidic oscillator according to claim 29 further comprising adjustable means for selectively limiting ambient air inflow to said interaction region to. a sufficient extent as to prevent establishing of partial channel flow through said interaction region.

31. The oscillator according to claim 30 wherein said adjustable means comprises an outer wall for said oscillator, said outer wall being adjustably positioned longitudinally relative to said guide wall such that in its fully extended position it projects beyond the downstream end of said guide wall and in its fullyretracted position it terminates upstream of the downstream end of said guide wall.

32. A liquid spray apparatus employing a fluidic oscillator of the type which oscillates between a partial channel flow mode, in which liquid is issued from the oscillator as a high velocity compact annular jet, and a full channel flow mode, in which liquid is issued from said oscillator in a relatively low velocity, unaerated annular spray pattern, said oscillator further comprising adjustment means for selectively inhibiting oscillation and said partial channel flow modle by establishing and steadily maintaining said full channel flow mode.

33. The apparatus according to claim 32 wherein said adjustment means includes a flow passage for introducing ambient air into said channel and which is controllably closable to initiate said full channel flow mode.

34. A fluidic oscillator comprising: an interaction region in the form of a flow channel having an inlet end, an outlet end and an outlet opening defined through said outlet end, said outlet opening being substantially narrower than said outlet end; I i

a power nozzle arranged to issue pressurized liquid into said inlet end of said interaction region, said power nozzle being positioned such that, upon issuance of said pressurized liquid into said interaction a feedback passage arranged to conduct ambient air region in the presence of ambient air, a partial channel flow state is established wherein a compact liquid jet is formed and issues through said outlet opening, and such that, upon issuance of said pressurized liquid into said interaction region in the absence of ambient air, a full channel flow state is established wherein said pressurized liquid diffuses and fills said interaction region before issuing from outlet opening; and

into said interaction region in response to outflow from said outlet opening in said full channel flow state and to inhibit entry of ambient air to said interaction region in response to outflow from said interaction region in said partial channel flow state. 5

35. The fluidic oscillator according to claim 34 further comprising a flow guide wall arranged to guide outflow from said outlet opening in said partial channel flow state, said guide wall having an ingress opening to said feedback passage defined therethrough at a location which is blocked to ambient air by said outflow in said partial channel flow state.

36. The oscillator according to claim 35 wherein the downstream end of said interaction region is configured as a smooth narrowing transition from the widest part of said interaction region to said outlet opening, and wherein velocity augmentation of said outflow occurs at the onset of each full channel flow state l l l 

1. A fluidic oscillator comprising: an interaction region having upstream and downstream ends, a substantially straight sidewall terminating abruptly proximate said downstream end, and a curved sidewall which diverges gradually from said straight sidewall in a downstream direction and curves sharply back toward said straight sidewall at said downstream end, said curved sidewall terminating slightly downstream of said straight sidewall, the terminations of said sidewalls defining an outlet opening at the downstream end of said interaction region; a power nozzle located at the upstream end of said interaction region and arranged to issue a jet of pressurized liquid into said interaction region, said jet being directed by said power nozzle generally adjacent said straight sidewall such that said jet issues undeflected through said outlet opening when ambient air is present in sufficient quantity in said interaction region to limit jet flow therethrough to a partial channel flow mode, said jet being deflected by said sidewalls to issue from said outlet opening at an angle into the plane of said straight sidewall when ambient air is sufficiently absent from said interaction region to cause said jet to assume a full channel flow mode therein; and a feedback passage having an ingress opening and arranged to conduct ambient air to said interaction region when said ingress opening is unblocked, said ingress opening being positioned downstream of said outlet opening so as to be blocked to ambient air inflow when said liquid jet issues undeflected from said outlet opening and open to ambient air inflow when said liquid jet issues deflected from said outlet opening.
 2. The oscillator according to claim 1 formed as an axi-symEtrical element wherein said power nozzle, said interaction region and said outlet opening have annular transverse cross-sections which are concentric about said feedback passage, said interaction region having a longitudinal cross-section with a semi-teardrop configuration.
 3. The element according to claim 1 further comprising a flow guide wall extending downstream from the termination of said curved sidewall and positioned to guide said liquid jet when issuing from said outlet opening undeflected, and wherein said ingress opening for said feedback passage comprises an opening defined in said guide wall.
 4. The oscillator according to claim 3 wherein said feedback passage terminates in a control port opening through said curved sidewall into the upstream end of said interaction region.
 5. The oscillator according to claim 4 constructed as an axisymmetrical element about said feedback passage, wherein said power nozzle, said interaction region and said outlet opening have annular transverse cross-sections which surround said feedback passage, and wherein said curved sidewall comprises the radially innermost wall of said interaction region.
 6. The oscillator according to claim 5 further comprising an annular outlet region extending downstream of said outlet opening and having as its inner boundary wall said flow guide wall.
 7. The oscillator according to claim 6 further comprising an outer wall for said annular outlet region arranged to guide said liquid jet when it issues deflected from said outlet opening.
 8. The oscillator according to claim 7 wherein said outer and inner walls of said outlet region diverge from one another in a downstream direction.
 9. The oscillator according to claim 7 wherein said outer and inner walls of said outlet region converge toward one another in a downstream direction.
 10. The oscillator according to claim 7 wherein said interaction region has a sufficiently large volume to delay the deflected jet issued from said outlet opening relative to the undeflected jet issued from said outlet opening.
 11. The oscillator according to claim 7 further comprising: a hollow housing having a first interior wall section of straight cylindrical configuration defining one side of said annular power nozzle and said straight sidewall of said interaction region, said housing having a second interior wall section downstream of said first interior wall section and defining said outer wall of said outlet region; and member means disposed symmetrically within said hollow housing and spaced radially inward from said first and second interior wall sections of said hollow housing, said member means including: a first peripheral wall section of generally cylindrical configuration defining a second side of said annular power nozzle; a second peripheral wall section downstream of said first peripheral wall section and which at its upstream end is generally parallel to the first interior wall section of said hollow housing and then diverges and curves in a downstream direction to define said curved sidewall of said interaction region; and a third peripheral wall section defining said flow guide wall.
 12. The oscillator according to claim 7 wherein the longitudinal position of the outer wall of said outlet region is movable relative to said flow guide wall.
 13. The oscillator according to claim 12 wherein the outer wall of said outlet region comprises a generally cylindrical member surrounding the downstream portion of said oscillator and is longitudinally movable relative to said straight sidewall of said interaction region.
 14. The oscillator according to claim 13 wherein said outer wall, in its fully retracted extreme upstream position, projects slightly downstream of said outlet opening and terminates upstream of said feedback openings in said flow guide wall; and wherein said outer wall, in its fully protracted extreme downstream position, projects beyond the downstream termination of said flow guide wall.
 15. The Oscillator according to claim 14 wherein said outer wall and said flow guide wall define a sufficiently narrow outlet region when said outer wall is fully protracted to limit ambient air inflow to less than that required to permit partial channel flow through said interaction region over a relatively wide range of liquid supply pressures.
 16. The oscillator according to claim 14 wherein said outer wall, in its fully retracted position, defines a relatively narrow outlet opening with said flow guide wall such that for low liquid supply pressures the liquid outflow during said full channel flow mode blocks all entry into said feedback openings and said interaction region and maintains said fully channel flow mode to prevent oscillation; and such that for higher pressures said liquid outflow during said full channel flow mode is sufficiently turbulent to permit ambient air to enter said feedback openings and maintain oscillation between said full and partial channel flow modes.
 17. The oscillator according to claim 13 further comprising a fluid passage defined between said outer wall and the downstream portion of said oscillator, said fluid passage being arranged to conduct ambient air inflow to said interaction region when said outer wall is fully protracted and to be blocked to ambient air inflow when said outer wall is fully retracted.
 18. The oscillator according to claim 7 further comprising adjustable flow restriction means located in said feedback passage to permit controlled adjustment of the duty cycle of said oscillator.
 19. The oscillator according to claim 18 wherein said adjustable flow restriction means has an extreme position in which said feedback passage is blocked to fluid flow, thereby limiting operation of said oscillator to its full channel flow mode.
 20. The oscillator according to claim 18 wherein said adjustable flow restriction means comprises a needle valve projecting into said feedback passage from the downstream end of said oscillator and having an adjustment control located at the downstream end of said oscillator.
 21. The oscillator according to claim 7 operable as a shower head and further comprising mounting means for securing said oscillator to a liquid supply in a shower plumbing installation.
 22. The oscillator according to claim 7 operable as a sink faucet adapter and comprising means for securing said oscillator to a sink faucet.
 23. The oscillator according to claim 7 arranged to provide decorative fountain spray patterns, wherein said flow guide wall extends a relatively long distance downstream of the outer wall of said outlet region.
 24. The oscillator according to claim 23 further comprising an annular divider disposed about said guide wall proximate the downstream end of said guide wall, said flow divider including at least one longitudinally-extending opening positioned to conduct a portion of the liquid flowing along said guide wall through said flow divider, said flow divider being contoured to outwardly deflect that portion of the liquid which does not pass through said opening.
 25. A fluidic oscillator comprising: an interaction region of annular transverse cross-section having upstream and downstream ends, a substantially straight outer cylindrical sidewall terminating abruptly proximate said downstream end, and a curved inner sidewall which diverges gradually from said straight sidewall in a downstream direction and curves sharply back toward said straight sidewall at said downstream end, said curved sidewall terminating slightly downstream of said straight sidewall, the terminations of said sidewalls defining a single annular outlet opening at the downstream end of said interaction region; an annular power nozzle located at the upstream end of said interaction region and arranged to issue an annular flow of pressurized liquid into said interaction region, said annular flow being directed by said power nozzle generally along said straight sidewall such that said annular flow issues Undeflected through said outlet opening when ambient air is present in sufficient quantity in said interaction region to limit flow therethrough to a partial channel flow mode, said annular flow being deflected by said sidewalls to issue from said outlet opening at an angle into the cylindrical plane of said straight sidewall when ambient air is absent from said interaction region to cause said annular flow to assume a full channel flow mode therein; and a feedback passage having an ingress opening and arranged to conduct ambient air to said interaction region when said ingress opening is unblocked, said ingress opening being positioned downstream of said outlet opening so as to be blocked to ambient air inflow when said annular flow of liquid issues undeflected from said outlet opening and open to ambient air inflow when said annular flow of liquid issues deflected from said outlet opening.
 26. The fluidic oscillator according to claim 25 further comprising adjustable means for selectively limiting ambient air inflow to said interaction region to a sufficient extent as to prevent establishing of partial channel flow through said interaction region.
 27. The fluidic oscillator according to claim 26 wherein said adjustable means comprises a valve disposed in said feedback passage.
 28. The oscillator according to claim 26 wherein said adjustable means comprises an outer wall for said oscillator, said outer wall being adjustably positioned longitudinally relative to said oscillator such that in its fully extended position it projects beyond the downstream end of said oscillator and in its fully retracted position it terminates upstream of the downstream end of said oscillator.
 29. The oscillator according to claim 25 further comprising a generally cylindrical flow guide wall extending downstream from the termination of said curved sidewall and positioned to guide said annular flow of liquid when it issues from said outlet opening undeflected.
 30. The fluidic oscillator according to claim 29 further comprising adjustable means for selectively limiting ambient air inflow to said interaction region to a sufficient extent as to prevent establishing of partial channel flow through said interaction region.
 31. The oscillator according to claim 30 wherein said adjustable means comprises an outer wall for said oscillator, said outer wall being adjustably positioned longitudinally relative to said guide wall such that in its fully extended position it projects beyond the downstream end of said guide wall and in its fully retracted position it terminates upstream of the downstream end of said guide wall.
 32. A liquid spray apparatus employing a fluidic oscillator of the type which oscillates between a partial channel flow mode, in which liquid is issued from the oscillator as a high velocity compact annular jet, and a full channel flow mode, in which liquid is issued from said oscillator in a relatively low velocity, unaerated annular spray pattern, said oscillator further comprising adjustment means for selectively inhibiting oscillation and said partial channel flow mode by establishing and steadily maintaining said full channel flow mode.
 33. The apparatus according to claim 32 wherein said adjustment means includes a flow passage for introducing ambient air into said channel and which is controllably closable to initiate said full channel flow mode.
 34. A fluidic oscillator comprising: an interaction region in the form of a flow channel having an inlet end, an outlet end and an outlet opening defined through said outlet end, said outlet opening being substantially narrower than said outlet end; a power nozzle arranged to issue pressurized liquid into said inlet end of said interaction region, said power nozzle being positioned such that, upon issuance of said pressurized liquid into said interaction region in the presence of ambient air, a partial channel flow state is established wherein a compact liquid jet is formed and issues through said outlet opening, and such that, upon issuance of said pressurized liquid into said interaction region in the absence of ambient air, a full channel flow state is established wherein said pressurized liquid diffuses and fills said interaction region before issuing from outlet opening; and a feedback passage arranged to conduct ambient air into said interaction region in response to outflow from said outlet opening in said full channel flow state and to inhibit entry of ambient air to said interaction region in response to outflow from said interaction region in said partial channel flow state.
 35. The fluidic oscillator according to claim 34 further comprising a flow guide wall arranged to guide outflow from said outlet opening in said partial channel flow state, said guide wall having an ingress opening to said feedback passage defined therethrough at a location which is blocked to ambient air by said outflow in said partial channel flow state.
 36. The oscillator according to claim 35 wherein the downstream end of said interaction region is configured as a smooth narrowing transition from the widest part of said interaction region to said outlet opening, and wherein velocity augmentation of said outflow occurs at the onset of each full channel flow state. 